[MarvinRio]

How to assign null or clean the resultset when nothing is found? example:
Select name from names where code = 0;

When this search does not return anything, I would like the resultset returned null because nothing was found, what is happening is that the resultset only updates the value when a result is found, when no result is found it keeps the last value, and when someone enters a name that does not exist in the table it always returns the last name found, this error delayed me a lot, and I found nothing that I could understand to solve my problem, thanks a lot guys! Have a nice day.

Note : I use Java.

[CasiOo]

Can you show us the code where you are querying the database?

[MarvinRio]

CasiOo, on 10 November 2013 - 07:48 AM, said:

Can you show us the code where you are querying the database? />

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.logging.Level;
import java.util.logging.Logger;




public class FrameAcessoBanco extends javax.swing.JFrame {

    /**
     * Creates new form FrameAcessoBanco
     */
    public FrameAcessoBanco() {
        initComponents();
    }

    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        jButton1 = new javax.swing.JButton();
        field = new javax.swing.JTextField();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jButton1.setText("GO!");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(field, javax.swing.GroupLayout.PREFERRED_SIZE, 155, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(18, 18, 18)
                .addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 86, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(131, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(38, 38, 38)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                    .addComponent(field)
                    .addComponent(jButton1, javax.swing.GroupLayout.DEFAULT_SIZE, 40, Short.MAX_VALUE))
                .addContainerGap(106, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>                        

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        String teste = field.getText();
        try{


Connection con = DriverManager.getConnection("jdbc:derby://localhost:1527/Banco","Ramom","banco123");

Statement st = con.createStatement();

ResultSet rs = st.executeQuery("SELECT name from app.names where codigo="+teste);

while(rs.next()){
System.out.println(rs.getString(1));

}

}
catch(Exception e){

}
    }                                        

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(FrameAcessoBanco.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(FrameAcessoBanco.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(FrameAcessoBanco.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(FrameAcessoBanco.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new FrameAcessoBanco().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    public javax.swing.JTextField field;
    private javax.swing.JButton jButton1;
    // End of variables declaration                   
}

[MarvinRio]

This is a short exemple, Thank you my friend! I like it when the search does not find anything, I could clean the resultset or set null inside. so I can use the IF when he was null, so I need to clean it.
Thank you again my friend! Very thanks for atention !

[CasiOo]

I don't see why your above example would behave as you described, sorry

[MarvinRio]

CasiOo, on 10 November 2013 - 09:08 AM, said:

I don't see why your above example would behave as you described, sorry

I understand, I can not post all the code as it is not the company, I just want to clear the resultset because it only updates the data when he gets a valid value when it does not find the value, it keeps the old value and keeps repeating the old value to a new value that someone type in a name to search the table table possesses. Do you know any way to clean the resultset?

[CasiOo]

So the code you posted is not the actual code you are having trouble with?
Are the "bugs" present in the code posted?